Unsaturated acyl isothiocyanates and method of making the same



State Paten 951 c 7 H 2,877,244 Patented Mar, 10, 195294:

9 Claims. or. 260-4025 invention relates tonovel unsaturated acylisothio cyanatesv and:.-to--a method of making the same. Moreparticularly, th e invention is concerned with a novel'classof-.chemical compounds having one-or'more-polymerizablea-ethylenicallyunsaturated .carbon-to-carbon double bonds in-their molecules togetherwith an NCS-group attached toaicarboxyl group.-@Unsaturatedisothiocyanates the NCS-groups of which being attached toa'hydrocarbon radical have been known for-a relatively long time. Theycan,-for instance, be produced by. the action of thiophosgene-onunsaturated amines such--as allyl amine. Furthermore, it is known tosplit g-thioureas withconcentr-ated acids or to split ofihydrogen halidefrom-saturated isothiocyanates containing halogen. Another class ofunsaturated isothiocyanates the NCS-groups of which-being attached-,toaromatic rings can be produced for instance, by a method disclosed inour co-pending U. S. patent application Serial No. 555,743, filedDecember'28, 1955. According to the procedure claimed with thatapplication unsaturated acyl halides are condensed with hydroxy arylisothiocyanates.

It is an object of the present invention to provide aliphaticunsaturated isothiocyanates which have polymerizable ethylenicallyunsaturated carbon-to-carbon double bonds. 1 \rr Another object is toprovide unsaturated isothiocyanates which may be copolymerized withvinyl or allyl compounds and reacted with compounds having activehydrogen to give useful plastics. A further object-is to provide aprocess for preparing the unsaturated acyl isothiocyanates. Still".further objects will appear-hereinafter.

It has now been found that unsaturated acyl isothiocyanates can beproduced in a good yield if aliphatic unsaturated acyl halides arereacted in inert organic media with inorganic thiocyanates.

The reaction of the present invention proceeds in accordance with thefollowing equation:

in which R is an aliphatic radical with polymerizable ethylenicallyunsaturated carbon-to-carbon double bonds, X is chlorine, bromine oriodine and A is a metal or an inorganic cationic group such as ammonium.

Illustrative examples of aliphatic unsaturated acyl halides which may beused in the practice of the invention include acrylic acid chloride,acrylic acid bromide, acrylic acid iodide, methacrylic acid chloride,methacrylic acid bromide, methacrylic acid iodide, crotonic acidchloride, crotonic acid bromide, crotonic acid iodide. Further examplesare the chlorides, bromides and iodides of sorbic acid, cyano sorbicacid, chloracrylic acid, cyano acrylic acid, methyl crotonic acid, oleicacid or pentane-S- carboxylic acid.

Representatives of inorganic thiocyanates are, for instance, sodiumthiocyanate, potassium thiocyanate, calcium thiocyanate, strontiumthiocyanate, magnesium thiocyanate, ammonium. thiocyanate,. leadthiocyanate, ferric thiocyanate,. cuprous. thiocyanate, aluminumthiocyanate and silver thiocyanate. a 1

'In carrying .out the process of the invention, the. abovedefinedunsaturated aliphatic acyl halides are brought together with theinorganic thiocyanate in an inert solvent in an equimolar or nearlyequimolar amount. In some instances, however, it is preferred to employan excess of inorganic thiocyanatessinorder to obtain better yields.;Organic solvents which can be employed in -the process of, theinvention and which .willnot react with theracyl thiocyanates; producedby the process include :benzene, toluene, acetone, tetrahydrofurane,dioxane, methyl ethyl ketone,- diallyl ketone, diisopropyl ketone andcyclohexanone. 7 U

iSince-the-novel unsaturated acyl isothiocyanates can polymerize-evenwhile they are being produced owing ,to their activated double bond itis preferred to carry out the reaction in the presence-of polymerizationstabilizers. As polymerization stabilizersany stabilizer known in thepolymerization technique can be used. Examples of suitable compounds ofthis kind are pulverulent copper, coppersalts such as copper oleate,sulfur, quinone, quinhydrone, phenthiazine, the diacetate ofthiodiglycol and thediethyl ester ofthiodibutyric acid.

v Thereaction between the acyl halide and the inorganic thiocyanate isexothermic. The reaction is. therefore started-preferably at roomtemperature. When the temp'eraturemises up to'the boiling point ofthe-solvent ex: terna1-cooling1may become necessary. According to-apreferred embodiment reaction is performed under reflux. The novelunsaturated acyl isothiocyanates can be prepared, for example, in thefollowing manner:

The acyl halide-is introduced with stirring into a' suspension of.v apowdery inorganic thiocyanate in. an inert organic medium. Anappreciable rise in temperature then-occurs. After all, .the'unsaturated acyl halide has been added. The mixtureis preferably stirredfor several moreehours at reflux temperature. After cooling theinorganic lprecipitate which has formed can be filtered off withsuctionor washed out with water. The isothiocyanate which is obtained isthereafter distilled off in vacuo. 1

The novel compounds are colorless to slightly yellow liquids which caneasily be distilled in vacuo. -..The smooth progress of the reactionaccording to the present invention was not to be expected since therewas a strong possibilityof the NCS-group being added to the activateddouble bondof the unsaturated halide or acyl isothiocyanate,-especially,as the reaction is usually carried out atanacid'pI-Ivalue. t I Thenovel-aliphaticethylenically unsaturated acyl isothiocyanates aresuitable as intermediate products for the production of plastics andpharmaceutical products. Thus, for instance, they can be copolymerizedwith other known unsaturated vinyl or allyl compounds such as vinylchloride or styrene. The copolymers obtained can be reacted in a secondphase with compounds containing active hydrogen atoms to give valuablehigh molecular weight plastics. Another utility of the products of theinvention is to copolymerize the unsaturated acyl isothiocyanates withoxypyrrolidones to produce high molecular weight blood detoxicatingagents.

The following examples illustrate the process of the invention withoutin any way limiting it. Parts given are parts by weight.

Example 1 parts of potassium thiocyanate are finely ground and suspendedin 400 parts of acetone by stirring. 0.5 part of phenthiazine is addedto prevent polymerization.

105 parts of methacrylic acid chloride are then added dropwise. Duringthis reaction, the temperature quickly rises to 50 C. The temperature ismaintained for another 2 hours at 50 C. and the mixture is mixed with500 parts of benzene and 1000 parts of water after cooling. The organicphase is separated, washed neutral several times with sodium chloridesolution and dried with sodium sulphate. After the drying operation, thebenzene is driven off in vacuo. The residue is distilled in a water jetvacuum.

B. P. 18 mm 60 C. Yield 110 parts.

Example 2 170 parts of potassium thiocyanate are stirred with 800 partsof acetone, as described in Example 1. 170 parts of crotonic acidchloride are now added dropwise. The mixutre is thereby heated to 50 C.It is stirred for another 2 hours at this temperature, diluted aftercooling with 800 parts of benzene and 1500 parts of water and theorganic phase is separated out. After washing several times with sodiumchloride solution, the substance is dried with sodium sulphate and thenthe benzene is distilled off at reduced pressure. The residue issubjected to distillation in a water jet vacuum:

B. P. 17 mm 78-80" C. Yield 205 parts.

Example 3 90 parts of powdered and dried sodium thiocyanate arcsuspended in 400 parts of benzene containing 0.5 part of phenthiazine.87 parts of acrylic acid chloride are then added dropwise whilestirring, the temperature quickly rising to 50 C. The mixture is stirredfor another 2 hours at this temperature. After cooling, the substance ismixed with 400 parts of benzene and filtered with suction from theseparated potassium chloride. 102 parts of acryloyl isothiocyanate areobtained by distillation.

B. P. 25 mm 5658' C.

Example 4 300 parts of oleic acid chloride are dropped into a suspensionof 55 parts of magnesium thiocyanate in 800 parts of benzene. Thetemperature slowly rises and the mixture is stirred for another 2 hoursat 60 C. The re action mixture is filtered with suction while stillbeing hot. The residue is washed out with benzene. The benzene of thebenzene solution of oleic acid isothiocyanate is driven off in a waterjet vacuum. 250 parts of oleic acid isothiocyanate are obtained as apale yellow oil.

Example 5 175 parts of sorbic acid bromide are dropped into a suspensionof 190 parts of lead thiocyanate in 800 parts of diethyl ketone. Leadbromide is precipitated while the temperature rises. The reactionmixture is stirred for another hour at 60 C. and then poured into water.The sorbic acid isothiocyanate which is separated out is dissolved inbenzene and washed neutral with water. The benzene solution is driedwith sodium sulfate and the -7 if i solvent driven off in a water jetvacuum- .The residue is distilled in a high vacuum. There are obtained100 parts of the nearly colorless sorbic acid isothiocyanate.

While certain representative embodiments and details have been shown forthe purpose of illustrating this invention, it will be apparentto thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit and scope of the-inventionexcept as set forth in the claims.

What is claimed is:

1. Compounds having the formula RCONCS, wherein R represents the radicalof an ethylenically unsaturated hydrocarbon derived from a fatty acid.

2. A process for the production of compounds having the formula RCONCS,wherein R represents the radical of an ethylenically unsaturatedhydrocarbon derived from a fatty acid which comprises reacting halidesof organic carboxylic acids containing polymerizable ethylenicallyunsaturated carbon-to-carbon doublebo'nds with incrganic thiocyanates. Vp

3. A process for the production of compounds having the formula RCONCS,wherein R represents the radical of an ethylenically unsaturatedhydrocarbon derived from a fatty acid which comprises reacting in inertorganic media halides or organic carboxylic acids contain ingpolymerizable ethylenically unsaturated carbon-tocarbon double bondswith inorganic thiocyanates.

4. A process for the production of compounds having the formula RCONCS,wherein R represents the radical of an ethylenicaly unsaturatedhydrocarbon derived from a fatty acid which comprises reacting in thepresence of polymerization stabilizers and in inert organic mediahalides of organic carboxylic acids containing polymerizableethylenically unsaturated carbon-to-carbon double bonds with inorganicthiocyanates.

5. Methacrylic acid isothiocyanate 0 CHz=C -N=C=B $113 6. Crotonic acidisothiocyanate I CHa=CH C-N=C==S 8. Oleic acid isothiocyanate CH CHCH=CH (CH CONCS 9. Sorbic acid isothiocyanate E H II CHaGH=CC=CH-C-N=C=S No references cited.

1. COMPOUNDS HAVING THE FORMULA RCONCS, WHEREIN R REPRESENS THE RADICALOF AN ETHYLENICALLY UNSATURATED HYDROCARBON DERIVED FROM A FATTY ACID.2. A PROCESS FOR THE PRODUCTION OF COMPOUNDS HAVING THE FORMULA RCONCS,WHEREIN R REPRESENTS THE RADICAL OF AN ETHYLENICALLY UNSATURATEDHYDROCARBON DERIVED FROM A FATTY ACID WHICH COMPRISES REACTING HALIDESOF ORGANIC CARBOXYLIC ACIDS CONTAINING POLYMERIZABLE ETHYLENICALLYUNSATURATED CARBON-TO-CARBON DOUBLE BONDS WITH INORGANIC THIOCYANATES.